Gas Recombination Vent Plug for Flooded Lead Acid Batteries

Gas Recombination Vent Plug for Flooded Lead Acid Batteries Dr S N Joshi, DirectorTechnical, Greenvision Tech. Pvt. Ltd. M.S.Hegde, Solid State structural chemistry, Indian Institute of Sciences, Bangalore.India.

Greenvision Technologies Pvt. Ltd Executive Summary Incorporated in March 2008 at Bangalore, India. ISO 9001 & ISO 14001 certified. State of the art manufacturing facility with annual capacity of 400 million Ampere hours 372 employees Products AGM & GEL VRLA Batteries for UPS, Solar, Telecom & other industrial applications, Tubular Flooded batteries for inverter and solar applications. Dealer network of 3000+ dealers across India with service centers at 64 locations. Install base of more than 3.5 million batteries in India. Qualified and experienced management team. Products designed and developed by a dedicated R&D team for UPS, Solar & Telecom applications.

Pan India Sales & Service Network NORTH SOUTH EAST WEST New Delhi Bangalore Kolkatta Mumbai Gurgaon Hubli Siliguri Goa Chandigarh Mangalore Patna Pune Jammu Chennai Ranchi Aurangabad Ludhiana Coimbatore Bhubneshwar Nagpur Parvanoo Madurai Guwahati Nasik Dehradun Pondicherry Jamshedpur Ahmedabad Jaipur Secunderabad Baroda Jodhpur Vijaywada Rajkot Agra Vishakhapatnam Surat Lucknow Calicut Gandhidam Gaziabad Cochin Indore Varnasi Kottayam Bhopal Amritsar Trivandrum Jabalpur Kanpur Rajamundry Raipur Karnal Mysore Kohlapur Panipat Trichy Haldwani Srinagar

Manufacturing Plant

Lead Acid Batteries in electrical systems Standby electrical systems: inverter, uninterruptable power supply, power generating stations, power sub-stations, telecommunication exchanges, solar photovoltaic systems Lead acid standby batteries working in such installations require maintenance in terms of water topping up into the battery cell. Battery life is dependent on sufficient acid level throughout its functioning.

Maintenance of Flooded Lead Acid Batteries Problem of water loss due to electrolysis is inherent property of a dynamic system where standby lead acid storage battery is connected to an electrical system Manufacturers of batteries and their service team members or the users of batteries need to attend to such maintenance procedures. Many times due to lack of trained personnel batteries fail prematurely. Water topping up is major and painful process. Visit of service engineer, spillage, grounding.

Catalytic plugs for lead batteries For many years catalysts are tried and tested for various industrial of applications for recombination of hydrogen & oxygen gases. Tungsten carbide was as internal gas recombination catalyst during 1990. However, it was never implemented. AquaGen is the only commercial product available in the market for flooded type lead acid batteries for 30+ years. MICROCAT developed by EAST PENN remains their own proprietary product mainly for DEKA UNIGY II 2V cells.

Maintenance Free Flooded Lead Acid Battery AquaSafe vent plug has been developed by using Noble metal ions based catalyst such as platinum & palladium ionized complex salts for recombination of gases into water. The honeycomb design gives large surface area contact for gases to recombine very efficiently. Design of plug consists of ceramic filter tube placed within a moulded plastic components. The parts are such that condensed water returns back into the cell. The catalyst function at room and elevated ambient temperatures & has same recombination efficiency all the times

Design of honey comb

Design of honey comb Design of RECOMB plug based on use of cordierite honeycomb structure for catalyst coating. The design has very high surface area for coating the catalyst. Nearly 600 holes / sq. inch The parallel walls structure provides large contact for the gases to react. Efficiency of reaction rate to nearly 99% at all currents. Stabilized crystalline metal salts network on surface of cordierite capture every gas molecule passing over it.

Catalyst functioning Working efficiency at high temperatures is improved by the honeycomb design of catalyst. Palladium salt works efficiently at temp.> 35 C Platinum salt works best at lower temperatures. However catalytic exothermic reaction keeps actually higher working temp. of honeycomb itself. Which makes it function superior with very high efficiency.

Catalyst coating Special proprietary process is executed on cordierite substrate to coat with desired quantity of catalyst to achieve required molecular structure. Chemical processing with stoichometric ratio is carried out for coating the catalyst. Higher firing temp. provides longer life to catalyst. X-ray diffraction pattern provides chemical structure of ionic salt complex.

X-ray diffraction pattern

Proposed structure of catalyst

AquaSafe vent plug features Catalyst coated cordierite is assembled in suitable thermo plastic molded components. Commercial product design of AquaSafe plug. Various threading types suitable to ISI / BS /JIS /DIN battery specification are also supplied. e.g. Threading types M27 / M30 / bayonet.

AquaSafe Vent plug

AquaSafe VENT PLUG cut section

Testing of catalyst plug 12V 150 Ah @ C/10 flooded - tubular positive plates battery was used with 5% Sb-Sn-As-Pb alloy. Emergency back up power - Inverter application. TESTS CONDUCTED: Effect of temperature on water loss at various float voltages -13.6, 13.8, 14.0,14.1, 14.4V 5 to 55 C Gas recombination efficiency found to be 99%. Water loss under cyclic test: 50 % DOD and 120 % recharge up to 15.8 V

Gas collection vs Recomb efficiency Water bath Temp. In C 25 ~ 27 43 ~ 45 58 ~ 60 Acid temp. C 26 48 53 Battery voltage 14.5 14.5 14.5 Float current 1.4 1.8 2.2 Volume of gas Collected in 15 minutes Recomb plug Temp. C 175 220 310 26 55 68

Test setup for Aquasafe plug

35 35 RISE IN RECOMB PLUG TEMPERATURE VS TIME RISE IN RECOMB PLUG TEMPERATURE VS TIME Avg recomb Temp C Acid temp C (Cell 3) Room temp( C) Voltage(V) Current(A) Avg recomb Temp C Acid temp C (Cell 3) Room temp( C) Voltage(V) Current(A) 0,40 0,40 Voltage(V) Voltage(V)& Avg Recomb Recomb Temp( C) Temp( C) 30 30 25 20 25 15 20 10 15 5 0 10 00:00:00 04:00:00 08:00:00 12:00:00 16:00:00 20:00:00 24:00:00 28:00:00 32:00:00 36:00:00 40:00:00 44:00:00 48:00:00 0 4 8 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 96 52:00:00 56:00:00 Time(in hours) 60:00:00 Time(in hours) 64:00:00 68:00:00 72:00:00 76:00:00 80:00:00 84:00:00 88:00:00 92:00:00 96:00:00 0,35 0,35 0,30 0,30 0,25 0,25 0,20 0,20 0,15 0,15 0,10 0,10 0,05 0,05 0,00 0,00 Current(A) Current(A)

Recomb temp-outer( C) Plug insidetemp( C) Recomb temp(outer surface) Recomb temp(plug inside) Voltage(V) Current(A) 120 C 17,00 100 C 80 C 60 C 40 C 20 C Recomb behaviour @ High temp 0 C 11,00 Time (In Hours) 16,00 15,00 14,00 13,00 12,00 Voltage(V) Current(A)

Field installation No 1 : 7.5 KVA UPS, 20 nos. batteries with AquaSafe plugs

Field installations : 7.5 KVA UPS, 20 nos. batteries with AquaSafe plugs

Field installation No 2 : 7.5 KVA UPS, 20 nos. batteries with AquaSafe plugs

Field installation No 3 : 2 nos 12V 150Ah with AquaSafe in 1 KW SPV system

Advantages of AquaSafe plugs 1. Flooded lead acid batteries are made maintenance free. 2. Acid electrolyte level is maintained for working life of the battery. 3. Water topping up maintenance during service is eliminated. 4. Corrosion of terminals of the battery is virtually eliminated. [Due to acid mist, terminals get corroded, thereby increasing contact resistance.]

New designs of AquaSafe plug

Thank You!! Questions??